The present invention relates to intake apparatus for an internal combustion engine, and more specifically to an intake apparatus including an intake port for increasing incylinder gas motion such as tumble or swirl.
Gas motion in engine cylinder such as tumble or swirl is important to achieve stable combustion of diluted air/fuel mixture in a spark ignition internal combustion engine. Accordingly, engines of some types require an intake apparatus which can increase incylinder gas motion in wider engine operation region.
Japanese Patent Application First Publication No. 2002-54535 shows a gas motion control valve to increase incylinder gas flow by closing a half of the section of an intake port. Japanese Patent Application First Publication No. H06-159079 shows an intake apparatus including a partition dividing an intake port into upper and lower halves, and a gas motion control valve closing the lower half of the intake port, to increase a tumble ratio.